Processes for the production of
shaped articles

ABSTRACT

SHAPED ARTICLES, SUCH AS FOOD TRAYS AND THE LIKE, ARE PRODUCED BY COLD-FORMING POLYESTER, ESPECIALLY ORIENTED POLYETHYLENE TEREPHTHALATE, FILMS BELOW THE POLYESTER GLASS TRANSITION TEMPERATURE, HEAT SETTING AND QUENCHING. SLIGHT RELAXATION AT THE HEAT SETTING TEMPERATURE MAY BE EFFECTED TO IMPROVE DIMENSIONAL STABILITY. SHORT CYCLING TIMES CAN BE ACHEIVED BY USING A COLD-FORMING PUNCH OF LOW THERMAL CAPACITY, FOR INSTANCE A SHAPED COPPER SHEET, THROUGH WHICH THE SHAPED FILM IS HEATED WHILE HELD IN THE DEFORMED CONDITION. LIDS MAY BE APPLIED TO THE SHAPED ARTICLES BY MELT ADHESIVES. FOOD CONTAINERS SO FORMED ARE SUITABLE FOR HEATING IN BOTH CONVENTIONAL AND MICROWAVE OVENS.

DEFENSIVE PUBLICATIGN UNITED STATES PATENT AND TRADEMARK OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. f6, 1969, 869 O.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered seriesand are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheer.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent and Trademark Otfice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED DECEMBER 2, 1975 T94-L018 PROCESS FOR THE PRODUCTION OF SHAPED ARTICLES Kenneth Clarke, Kncbwerth, England, assignor to Imperial Chemical Industries Limited, London, England Filed Sept. 16, 1974, Ser. No. 506,543 Claims priority, application Great Britain, Sept. 20, 1973,

44,132/73; Nov. 23, 1973, 54,386/73 Int. Cl. 1329c 27/06 U.S. Cl. 156-69 5 Sheets Drawing. 22 Pages Specification Shaped articles, such as food trays and the like, are produced by cold-forming polyester, especially oriented polyethylene terephthalate, films below the polyester glass transition temperature, heat setting and quenching. Slight relaxation at the heat setting temperature may be effected to improve dimensional stability. Short cycling times can be achieved by using a cold-forming punch of low thermal capacity, for instance a shaped copper sheet, through which the shaped film is heated while held in the deformed condition. Lids may be applied to the shaped articles by melt adhesives. Food containers so formed are suitable for heating in both conventional and microwave ovens.

Dec. 2, 1975 K. CLARKE T941,0l8

PROCESSES FOR THE PRODUCTION OF SHAPED ARTICLES Original Filed Sept. 16, 1974 Sheet 1 of 5 I! A, 42 Q T -/2 M 1 i Dec. 2, 1975 K. CLARKE T941,018

PROCESSES FOR THE PRODUCTION OF SHAPED ARTICLES Original Filed Sept. 16, 1974 Sheet 2 of 5 r% f% A F/GO Dec. 2, 1975 K. CLARKE T941,018

PROCESSES FOR THE PRODUCTION OF SHAPED ARTICLES On'ginal Filed Sept. 16, 1974 Sheet 3 of 5 mg L N i fi\\\ W DC. 2, 1975 K. CLARKE PROCESSES FOR THE PRODUCTION OF SHAPED ARTICLES Sheet 4 of 5 Original Filed Sept. 16, 1974 Dec. 2, 1975 K. CLARKE T941,018

PROCESSES FOR THE PRODUCTION OF SHAPED ARTICLES Original Filed Sept. 16, 1974 Sheet 5 of 5 FIG. 

